Check if Asp.Net(Core) application is hosted in IIS

Question

How can I check inside the application if it is being hosted in IIS?

Answer 1

Check if the environment variable APP_POOL_ID is set.

public static bool InsideIIS() =>
    System.Environment.GetEnvironmentVariable("APP_POOL_ID") is string;

All of environment variables that iis sets on a child process

Answer 2

I've tried the answer by Branimir Ričko but found that it's not correct: this environment variable is also set when running under IIS express.

So here is my modified version:

static bool IsRunningInsideIIS() =>
    System.Environment.GetEnvironmentVariable("ASPNETCORE_HOSTINGSTARTUPASSEMBLIES") is string startupAssemblies &&  
 startupAssemblies.Contains(typeof(Microsoft.AspNetCore.Server.IISIntegration.IISDefaults).Namespace);